Method of making patterns for castings



Dec. 9, 1924- A. R. BRADEN METHOD or MAKING PATTERNS FOR CAS'TINGS Filed Nov. 22, 1920 Patented Dec. 9, 1924.

UNETEE fiTATES l,5l8,l33

PATENT @FHQE.

ALBERT R. BRADEN, OF BEVERLY, MASSACHUSETTS, ASSIGNOR T0 UNITED SHOE MACHINERY CORPORATION, OF PATERSON. NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF MAKING PATTERNS FOR CASTINGS.

Application filed November 22, 1920.

To all whom it may concern:

Be it known that I, ALBERT R. BRADEN, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain Improvements in Methods of Making Patterns for Castings, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to methods of :making patterns for castings, being especially applicable to the manufacture of .such. articles as clicking dies, which are in the form of closed figures of irregular contours. The production of these dies from strip steel in the manner usually followed, involving the heating of the stock and its gradual formation about a templet, is an operation requiring much skill, and is relatively slow and expensive. Vhile it is feasible to cast the dies in sand molds at a small cost, as far as the casting operation itself is concerned, the production of the patterns for making the molds has been so troublesome as to bar-their use in the casting of dies, of which, like clicking dies, but few are'east from each pattern.

An object of the present invention is to provide a simple procedure by which patterns may be made with a proper degree of accuracy at slight expense. This object I attain by first forming a strip of flexible material having the cross-section of-the object to be cast, and then bending the strip to the contour of said object. After thus producing the pattern proper, it is preferably mounted upon a carrieryto which it. may be secured by an adhesive. 1n the herein particularly described =n1ethod of pattern making, the pattern strip consists of plastic material, preferably given the desired crosssectional form, as of the clicking die stock, by forcing it through an opening similarly formed. The'costof sucha strip is trifling, and its after treatment easy.

A further object of the invention is to furnish a pattern in which the shrinkage of the casting is provded for. This is accomplished by holdingthe templet and pattern strip in a predetermined relation during the formation of the latter to the templet, to cause the pattern to be of such size that.

Serial No. 425,855.

the shrinkage will be allowed for. When the pattern strip has an inclined wall, as when it corresponds to clicking die stock, co-operation between the templet and strip at varying portions of the inclination will correspondingly alter the size of the pattern, permitting it to be made to the desired -de gree larger than the finished casting- The correct relation between the strip and templet may be attained by mounting the templet parallel to a supporting surface, placing the base of the strip upon the surface, and bending the strip to the templet.

Convenient means for perfomning the steps of my improved method and a pattern for a die made in accordance therewith are illustrated in the accompanying drawing, in which Fig. 1 showsan apparatus for producing the strip of patternmaterial;

Fig. 2 illustrates in perspective the arrangement of the templet with relation to the support and the co-operating strip during the step of bending;

gig. 3 is transverse section therethrough; an

Fig. 4, a perspective view of the completed pattern.

In making a pattern for use in casting clickin dies, there is first formed a pattern strip which is of generally triangular form, having a base 8 and opposite converging walls inclined fronrthe base, the inner of these walls, whenthe strip assumes the coutour of the die, being designated byltheletter a For this purpose I prefer to employ a plastic material, as beeswax, a mass M of which may be placedin a cylinder 10 of some such strip-producing apparatus as is illustrated in Fig. 10f the drawing. This cylinder is shown as carried upon asuitable base in a horizontal position, and has an upwardly extending tube .12, through which the plastic maybe introduced. The tube iszclosed by a head 14, and to enable pressure to be exerted upon the introduced mass to suffciently fill the cylinder, :the head is carried by a screw 16 threaded. through a yoke 18. which may be separably fixed across the top of the tube. lVith the yoke and head removed, the plastic is placed, if'necessary in successive charges, through the tube, and forced into the cylinder, upon thereturn of the head and yoke, by screwing down the forn'ier. At one extremity of the cylinder is a cap 20, from which is a reduced extension 22, shown as rectangular in cross-section, the lower wall of this extension being horizontal. In one of the side walls, and also along the bottom of the extension, is an opening 24, which, in the side wall, has a form corresponding to the section of a strip of clicking die stock, or to that of the die itself before it is sharpened. Bearing against the bottom wall of the extension and closing the opening therein is a table 26, mounted for move ment in a horizontal direction upon pairs of rollers 28, 28, the journals 30 of which are arranged. to travel. along depressions in spaced. su ')porting bars 32, 32 extendlng transversely of the base of the apparatus. Operating in the opposite end of the cylinder is a plunger 54, carried upon a threaded rod 36 a ranged to turn in a bearing Surrounding the rod, adjacent to the bearing, and having threaded engagement with the former. is a worm-wheel 40. lVith this worm-wheel meshes a worm 12 fixed upon a shaft 44 journaled upon. the base. The shaft carries a pulley 46 belted to a suitable source of power, which may be caused to communicate its rotation to the worm by means of a friction clutch 48. The rotation of the worm will be transmitted to the wormwheel, which will cause the longitudinal travel of the rod 36 and therefore the advance or retreat of the plunger 34 through the cylinder, the advancing movement pressing the plastic through the opening 24. It there emerges upon the table 26 in the form of the pattern strip, carrying the table with it upon its rollers, this continuing until a strip of the desired length has been formed. If neces sary, the mass within the cylinder may be warmed by a fluid-conveying pipe 50 coiled about the cylinder, the flow through this being controlled by a valve 52.

The formed strip is then to be bent to the outline oi? the die to be cast, this being best accomplished by the use of a templet, as is indicated at T in l iigsi 2 and 3, the external contour of which templet is that of the cutting edge of the die. The templet is mounted upon and parallel to a base or support 54-, having suitably spaced openings 56, 56 to receive posts 58 extending vertically through the support. Upon the posts are enlargements 60, on which the templet may rest, it being locked on each post by a wedgeshaped key 62 having a key-hole slot 64, the circular portion of which receives the full diameter of the upper extremity of the post, while the narrowed extension admits a reduced portion 66.

With the keys removed, templet openings are carried over the posts, the keys returned, and the templet locked by forcing the wedges to one side, so that their slots travel along the reduced portion 66 of the post. To permit the distance between the support and the templet to be varied, the posts are movable through the support openings, being urged outwardly from the base by helical springs 68 situated between the base and the post en largements. The outward movement of the templet is adjustably limited by means of nuts 70 engaging the threaded ends of the posts.

There having been determined the amount which the cast metal will shrink to reduce the transverse dimensions of the die from that of the mold space in which it is cast, the templet is adjusted by turning the nuts 70 until its distance from the support 541- is less than that between the base of the pattern strip and its apex. Consequently, when the inclined wall of the strip engages the templet, the transverse dimensions of the pattern which is produced in accordance with the templet contour will be increased over that of the casting by an amount depending upon the distance between the support and templet and upon the angle of the side wall 6. This adjustment of the templet may be caused to exactly compensate for the shrinkage.

This predetermlned arrangement having been made, the base 8 of the flexible pattern strip is placed upon the support with its wall 71 toward the templet, and is bent in accordance with the contour of said templet, as is particularly illustrated in Fig. 2. When the strip has been thus formed about the entire periphery of the templet, its ends are joined, as by heating and pressing to gether, and its base is placed upon a mounting board or carrier B, both the boa-rd and strip being coated with an adhesive fluid, as shellac, which acts to secure the elements to each other and also to protect themthe board against the absorption of moisture and the strip against abrasion. This completes the pattern, which may be utilized in the customary way for ]l)1OCl1l(Tl11g a sand mold, in which a die may be cast. It will be seen that every step of the method may be performed quickly and accurately by means of simple instrunientalities, without any particular skill being required on the part of the workman, and that the materials employed are relatively cheap, and may be used repeatedly for the production of different patterns.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of making patterns for castings, which consists in forming a strip of flexible material having the cross-section of the object to be cast, and bending the strip to the contour of said object.

2. The method of making patterns 'for castings, which consists in forming a strip of flexible material having the cross-section of the object to be cast, bending the strip to the contour of said object, and fixing the formed strip upon a carrier.

3. The method of making patterns for castings, which consists in forming a strip of flexible material having the cross-section of the object to be cast, bending the strip to the contour of said object, placing the formed strip upon a carrier, and applying an adhesive to the strip and carrier.

t. The method of making patterns for castings, which consists in forming a strip of plastic material having a cross-section corresponding to the object to be cast, and bending the strip to the contour of said object.

5. The method of making patterns for castings, which consists in forcing a strip of plastic material through an opening having the form of a cross-section of the object to be cast, and bending the strip to the contour of said object.

6. The method of making patterns for castings, which consists in forming a strip of wax under the influence of heat and pressure, bending the strip to the contour of the object to be cast, placing the formed strip upon a carrier, and applying shellac to the strip and carrier.

7. The method of making clicking die patterns, which consists in forming an opening corresponding to the cross-section of die stock, forcing plastic material through the opening to produce a pattern strip,

' bending the strip about a die templet, and

mounting the strip upon a carrier.

8. The method of making patterns for castings, which consists in forming a strip in accordance with a templet, the strip and templet during this formation being maintained in a predetermined relation to introduce into the pattern an allowance for shrinkage in the casting.

9. The method of making patterns for castings, which consists in forming a strip of flexible material having an inclined wall, and bending the strip to bring the inclined wall into agreement with the templet at predetermined portions of its inclination.

10. The method of making patterns for castings, which consists in forming a strip of flexible material having a base and an ininclined side wall, mounting a templet parallel to a supporting surface, placing the base of the strip upon the surface, and bending the strip to bring the inclined wall into agreement with the templet.

11. The method of making patterns for castings, which consists in forming a strip of flexible material having a base and an inclined side wall, mounting a templet at a predetermined distance from a supporting surface, placing the base of the strip upon the surface, and bending the strip to bring the inclined wall into agreement with the templet.

12. The method of making patterns for castings, which consists in mounting a templet in proximity to a support, fixing the templet in a position determined by the casting to be produced, and forming a pattern strip about the templet upon the support.

13. The method of making clicking die patterns, which consists in forming a pattern strip corresponding in cross-section to clicking die stock, mounting a die templet at a distance from a support determined by the casting to be produced, placing the base of the pattern strip upon the support, and bending an inclined wall of the strip into agreement with the templet.

In testimony whereof I have signed my name to this specification.

ALBERT R. BRADEN. 

